ldap: Fixed multiple regressions

[samsinsane]

• Match URL scheme with LDAP and LDAPS
• Retrieve attributes, scope and filter from URL query instead

These regressions were introduced in #3017

[bagder]

./ldap.c:864:5: warning: if with space (SPACEBEFOREPAREN)
   if (!query) {
     ^

[bagder]

As we're a bit tight on time to release, I'll amend this myself before merge.

[bagder]

Thanks!

[samsinsane]

Sorry about that, thanks for fixing it up and merging!